1. Field of the Invention
The present invention relates to a multilayer wiring board and a manufacturing method thereof.
2. Description of Related Art
Regarding multilayer wiring boards (multilayer wiring substrates), conventionally known processes of forming a wiring layer such as a conductor (conductive) circuit pattern on an insulating layer include: an additive process in which a wiring layer is selectively formed only in portions of a wiring pattern; a semi-additive process in which a primary layer that is formed on the entire surface of the multilayer wiring board base is selectively removed or masked in portions other than the portions of a wiring pattern, and a wiring layer is formed on the resulting primary layer in accordance with the remaining or exposed patterned primary layer; and a subtractive process in which a conductor (conductive) layer is formed on the entire surface of the base, a resist (photosensitive resin) layer is formed on the conductor layer and patterned by exposing, curing and thereafter developing it to remove unnecessary portions, and using the patterns of the remaining resist layer as a mask, the exposed portions of the conductor layer are removed by etching, etc., so that the portions other than the portions of a wiring pattern are removed selectively from the conductor layer, resulting in the formation of a wiring layer (see, for example, Patent document 1 below).    Patent document 1: Japanese Unexamined Patent Publication No. 2005-136282